The surface tension is actually the interfacial free energy per unit area. The surfactantadsorbs at interfaces of system and brings a notable change into the work to expandinterfaces. Surfactants, in most of cases lessen interfacial tension , however there arecase where they are used to augment it [1, 2].
Surfactants have specific structure having a group that shows repugnance forsolvent, called lyophobic group, and the other being strongly irresistible for solvent calledlyophilic group. The structure having lyophilic as well as lyophobic group in a samecompound is known as amphiphilic, diphillic or amphipathic structure. It is exactly this nature of surfactantmolecules that underlines their tendency to gather at interfaces. If water is being used asa solvent then lyophilic part may be regarded as hydrophilic and lyophobic part ashydrophobic one.
The polar or hydrophilic part is referred to as the head group and nonpolaror hydrophobic as the tail. The polar or hydrophilic part may have either positiveor negative charge, giving rise to cationic or anionic surfactants respectively, or may becomposed of polyoxyethylene chain, as in the most of the nonionic surfactants.
Thenonionic or the hydrophobic portion of the molecule is usually a flexible hydrocarbonchain although many compounds especially those of biological interest, may havearomatic hydrophobic group. Cholesterol, glycolipids, and fatty acids are amphipaths which also incorporate into cell membranes. Bile acids are steroid amphipaths used to digest dietary fats. There are also categories of amphipaths.
Amphipols are amphiphilic polymers that maintain membrane protein solubility in water without the need for detergents. The use of amphipols allows the study of these proteins without denaturing them. Bolaamphipathic molecules are those that have hydrophilic groups at both ends of a ellipsoid-shaped molecule.
Compared to amphipaths with a single polar "head," bolaamphipaths are more soluble in water. Fats and oils are a class of amphipaths.
They dissolve in organic solvents, but not in water. Hydrocarbon surfactants used for cleaning are amphipaths. Examples include sodium dodecyl sulfate, 1-octanol, cocamidopropyl betaine, and benzalkonium chloride. Amphipathic molecules serve several important biological roles. They are the primary component of the lipid bilayers that form membranes.
Sometimes there is a need to alter or disrupt a membrane. Here, the cell uses amphipathic compounds called pepducins that push their hydrophobic region into membrane and expose the hydrophilic hydrocarbon tails to the aqueous environment.
The body uses amphipathic molecules for digestion. Amphipaths are also important in the immune response. Amphipathic antimicrobial peptides have antifungal and antibacterial properties. The most common commercial use of amphipaths is for cleaning.
Soaps and detergents both isolate fats from water, but customizing detergents with cationic, anionic, or uncharged hydrophobic groups expands the range of conditions under which they function. Liposomes may be used to deliver nutrients or drugs. Amphipaths are also used to make local anaesthetics, foaming agents, and surfactants.
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Select basic ads. Create a personalised ads profile. Term What is the difference between simple and conjugated proteins? Definition Simple- only amino acids Conjugated- protein and nonprotein groups. Term What is the prosthetic group in a glycoprotein? Definition Carbohydrate. Term What is the general structure of collagen?
Definition 3 helicies twisted together. Term With collagen molecules, where can you find covalent bonding? Definition Between side chains. Definition Globular proteins. Term What does amino acid catabolism result in? Definition Urea synthesis. Term What is the isoelectric point? Definition pH where the net charge is zero. Term How are organic solvents and detergents denaturing agents? Definition Disrupts hydrophobic interactions.
Term How are reducing agents denaturing agents? Definition Converts disulfide bridges and disrupts H-bonds. Term How can an increase in salt [ ] be denaturing? Definition Because salt binds to charged protein groups and causes a loss of solubility. Causes a precipitation. Term How are heavy metals denaturing agents? Definition Disrupt salt bridges and bind to R-SH groups. Term How can an increase in temperature be a denaturing agent? Term How can mechanical stress be a denaturing agent?
Definition Disrupts Protein structure. Term What 4 ways can nitrogen be lost? Definition loss of epithelial cells, excretion of NH3 or urea, loss of undigested proteins, loss through sweat. Term Where is the site of amino acid catabolism? Generally and Specifically. Definition Liver in mitochondria and cytoplasm. Term What is NH3 eliminated as in our body?
Definition Urea. Term When NH2 is removed from amino acids, what is left? Definition Alpha keto acids. Term What can alpha keto acids form?
Term Glutamic acid undergoes deamination. Afterwards, what is formed? Term How is carbanoyl phosphate formed? Term What significant event happens after citrulline forms? Definition It escapes the matrix into cytoplasm. Term How is argininosuccinate formed? Term What does argininosuccinate break down into? Definition Fumarate and arginine. Term What are the products of the hydrolysis of arginine?
Definition urea and ornithine by enzymatic reactions. Term How does the [ ] of NH3 affect the rate of the urea cycle? Term What does high protein and starvation do to the urea cycle? Definition speeds it up. Term Where do the 2 amino groups in urea come from? Definition 1 from the interconversion of aspartic acid to pyruvate and the other from free ammonia created in gluconeogenesis. Term What to urea cycle intermediates are shared with the TCA cycle and how?
Definition Produces fumarate used in tca cycle and uses aspartate created by tca cycle. Term How many atp's are used in the urea cycle.
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